Your chambering guy

[wildchild]

I push my reamer with a flat face tool in the tailstock. I do not want my tailstock to influence the path of my reamer. I want the reamer to follow a prebored hole. I spec my chambering reamer to cut +.003 larger at the base and .002 at the shoulder than my reamer that I use to make my sizing die. If your dies do not size the brass body, you will have chambering and extraction problems. I have tried to ream a chamber with runout, but haven't succeeded.

Id guess using the tail stock makes one lost also in this game, JMO.
So mathamatically .002 at the shoulder must be about .002 at the neck, whats that do to the freebore length? Hope the customer is'nt shooting a short neck case with a particular bullet in mind.

 

[butchlambert]

You may want to read your post again. It makes absolutely no sense. I can run my reamer an extra .100 and it doesn't effect freebore, just .100 too much headspace. I see you haven't done any machine work either.

 

[butchlambert]

wildone, I know you are going to comment. What does .002 larger at the shoulder and .003 at the base have to do with freebore? Freebore is determined by the grind of your reamer. Did you think my .002 and .003 dimensions could be smaller that your reamer?

 

[wildchild]

wildone, I know you are going to comment. What does .002 larger at the shoulder and .003 at the base have to do with freebore? Freebore is determined by the grind of your reamer. Did you think my .002 and .003 dimensions could be smaller that your reamer?

I really hope that your logic of a set freebore on a reamer isnt effected when you make the chamber bigger than the print! You just cut the throut larger in Dia when ya cut the chamber larger thus causing it to lengthen...not?

 

[wildchild]

wildone, I know you are going to comment. What does .002 larger at the shoulder and .003 at the base have to do with freebore? Freebore is determined by the grind of your reamer. Did you think my .002 and .003 dimensions could be smaller that your reamer?

ill go about it this way, you know them pointed cone hats ya wear at your birthday party? say we were spin it on a imaginary centerline then we take the center line and move it off center so it makes a circle, what happens were the point of the hat was spinning (or cutting)?

 

[Millsaps75]

Butch isn't saying he's Oversizing by having runout. He has the shoulder and base ground larger on his chamber reamer than on his sizing reamer. He has a sizing reamer ground to a smaller size to cut his dies. I'm sure his throat is within a few tenths (.0001) of what his chamber reamer measures.

 

[Dana Estes]

Butch isn't saying he's Oversizing by having runout. He has the shoulder and base ground larger on his chamber reamer than on his sizing reamer. He has a sizing reamer ground to a smaller size to cut his dies. I'm sure his throat is within a few tenths (.0001) of what his chamber reamer measures.

Totally agree. Has nothing to do with "length" or free bore. Even buthch's too deep chamber cut would NOT change freebore only the datum line...

 

[wildchild]

Butch isn't saying he's Oversizing by having runout. He has the shoulder and base ground larger on his chamber reamer than on his sizing reamer. He has a sizing reamer ground to a smaller size to cut his dies. I'm sure his throat is within a few tenths (.0001) of what his chamber reamer measures.

I guess i dont know exactly what he's doing but I have both chambering and die reamers that come in pairs for this type of setup, id say my chambering reamer is what it is and my die reamer is made smaller for obvious reasons. Either i could say my chambering reamer is bigger than my die reamer or I could say my die reamer is smaller than my chambering reamer.
Im getting a chamber cut tomorrow with a .338 neck ill gauge pin it and report.
I had one cut awhile ago that was a .330 neck and a .331 was loose but a .332 wouldn't go.
I guess my whole point or question of this thread was to find what is the norm or an excepting tolerance in a cut chamber above what the print says. Some honest replys and some tap dancers, So I guess whats expected from the fellow and world of chambering smiths is "what ya get is what ya get dont throw a fit", and if its cut to print ya got lucky and if its bigger...well Sh$! happens.

 

[BoydAllen]

Another little thing, assuming that a proper pilot bushing selection was made, any enlargement of the chamber at its base, due to misalignment of the back of the reamer from the rotational CL of the spindle, would diminish as one moved forward in the chamber. Half way to the pilot it would be half as much, and so on. If you want to get really picky, even with a perfect barrel and chamber, differences in bore diameter result in very small but real differences in the distance from the bolt face at which a given bullet will contact the rifling...but this matters not, because we do the measurement for each barrel, and start from there. Luckily, I have a gunsmith that cuts chambers that allow me to interchange brass (with my reamer). I have the barrel sent to him, call and discuss how I want it cut, and it comes perfectly fitted to my action. When I inspect the marks that the rifling makes on a bullet (of a loaded round), they are all the same. Yes, I know that I am lucky.

 

[wildchild]

Another little thing, assuming that a proper pilot bushing selection was made, any enlargement of the chamber at its base, due to misalignment of the back of the reamer from the rotational CL of the spindle, would diminish as one moved forward in the chamber. Half way to the pilot it would be half as much, and so on. If you want to get really picky, even with a perfect barrel and chamber, differences in bore diameter result in very small but real differences in the distance from the bolt face at which a given bullet will contact the rifling...but this matters not, because we do the measurement for each barrel, and start from there. Luckily, I have a gunsmith that cuts chambers that allow me to interchange brass (with my reamer). I have the barrel sent to him, call and discuss how I want it cut, and it comes perfectly fitted to my action. When I inspect the marks that the rifling makes on a bullet (of a loaded round), they are all the same. Yes, I know that I am lucky.

Now thats what Im talkn about!

 

[Millsaps75]

Wildchild, I feel your pain. It can drive you crazy worrying about the details especially when you entrusted someone with your $350 barrel!! I've been a machinist for over 20 years and I run my own shop. So I'm lucky in that I do all my own work. I think all good smiths do the very best they can and try to hold chambers as close as humanly possible. They take great pride in it. Lots of those guys get work through word of mouth so it pays to do there best but as you know we don't live in a perfect world. Forgot to say I often do a cast of my chambers and they usually come out very close to print. I point that out because I consider myself a hobbiest and am quite sure the pros can hold tighter than me.

 

[jscandale]

Butch,

The freebore can in fact increase if the reamer runout is so severe that it cuts a larger diameter than the actual size of the reamer. By how much, hard to say, but if the diameter is increased in the neck/body, the axial diameter will also be increased further up the reamer toward the throat, but not as much since the pilot is the pivot point of the conical error. With the increasing diameter, the freebore will be advanced forward. I think it's a matter of splitting hairs, but a trigonometric calculation can be derived to figure just how much. Again, splitting frog hairs here.

With all of this said, in the end, they all work well somehow unless something is really out of alignment. There are truly many ways to skin a cat and I have seen many of them work well.

I can say that I am pretty sure that the reamers that I have used to date all cut the chamber specified in the reamer print since I can place the reamer in the freshly cut chamber and it is snug, especially the carbide reamers since they require a bit more pressure to cut over a HS reamer. I have grown to LOVE my carbide reamers, but that's for another thread.

JS

 

[butchlambert]

JS, I understand that. I think the wildone thinks that my reamer cuts a fat hole because my sizing reamer is smaller in diameter. I could spec my chambering reamer small or large, that is not the issue. If my brass is sized to the chamber, what else can you ask for? I have gone back and reread my post and just can't find where I said I cut a fat chamber. It is pretty simple to run your indicator into your fresh chamber and check your work.
The problem we have is an individual without basic machine shop knowledge preaching to us. Now I don't know what his gunsmith has done good or bad for him. He doesn't know my chambering method and has no way to critique my machining.

 

[jscandale]

JS, I understand that. I think the wildone thinks that my reamer cuts a fat hole because my sizing reamer is smaller in diameter. I could spec my chambering reamer small or large, that is not the issue. If my brass is sized to the chamber, what else can you ask for?

Oh, got it . I could certainly agree with that.

JS

 

[skeetlee]

I can promis everyone here that Butch needs not be told how to run a lathe, or set up a barrel. I wish i knew a fraction of what he knows. Lee